Start with the delivery constraint
Most email workflows fail because the attachment is larger than the receiving system allows, not because the PDF itself is invalid.
Before compressing, decide whether you need an email copy, an archive copy, or an upload copy. Those outputs do not always need the same compression level.
- Use lighter compression for contracts and text-heavy PDFs.
- Use stronger compression for image-heavy scans and draft review packets.
- Keep the original file until the recipient confirms delivery.
Use comparison instead of guesswork
Start with a moderate compression level and compare the output against the original on the pages that matter most.
Check signatures, dense text pages, charts, and any scanned stamp pages before sending the compressed version out.
When to stop compressing
Stop when the file is small enough for the channel and still looks trustworthy on both desktop and mobile.
If you need a second, smaller version, start again from the original instead of re-compressing the first output.
Frequently asked questions
What is a safe PDF size for email?
There is no universal number, but staying comfortably below common attachment limits is safer than sending a file that barely fits.
Will text become blurry after compression?
It should not if you start with a moderate setting. Always review text-heavy pages instead of assuming every reduction level is acceptable.